One of the most significant current health care challenges is treatment of heart failure (HF). There are approximately 5 million Americans currently diagnosed with this condition, and there are 400,000-700,000 new cases annually. The direct costs of treatment are estimated at $10-$38 billion with the majority of this cost attributable to patients with New York Heart Association Class III or IV disease. Much of this cost is a result of repeat hospitalization, which occurs in many cases because of inappropriate therapeutic drug regimen. This proposal seeks to develop a technology for combined bedside radionuclide angiography (RNA) and pulmonary artery catheterization (PAC) that can be employed in this population at reasonable cost in the CCU. By merging RNA and PAC, this system will yield LV and RV ejection fractions, right heart, pulmonary, and left atrial pressures, cardiac output, stroke volume, wall motion, pulmonary blood volume, and, most significantly, absolute RV and LV volume curves, so that pressure-volume relations can be examined. By providing this wealth of additional clinical data, which can be obtained repeatedly at low cost through use of a short-lived radiotracer, this system will enable much more thorough evaluation of such patients, including quantitative examination of the effects of interventions, such as dobutamine and IV diuretics, as well as assessments of response to therapeutic dose levels. It will therefore lead to improved diagnosis, allow drug dose levels to be more accurately determined, and improve prognostic assessment. Since much of the cost of this disease is attributable to the need for repeated hospitalization of decompensated patients, substantial reduction of overall cost can be realized. Improved prognostic evaluation can also have a profound benefit by more accurately identifying patients who are suitable for heart transplantation and/or coronary artery bypass. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE